People with severe mental disorders endure abuse around the world, caged, warehoused in institutions, and imprisoned. But those living chained to trees or concrete blocks in parts of Africa are among the most trapped, forgotten people on earth.

One way to end or reduce the reliance on this custom, some experts have argued, would be to introduce Western psychiatry — providing the shackled with diagnoses and medication. One religious leader in Ghana decided that the idea, despite concerns about the drugs and intimations of cultural imperialism, was worth testing. He ran a retreat, or prayer camp, where scores of people were chained.

Now, in the current issue of the The British Journal of Psychiatry, a team of Ghanaian and American researchers report results of an experiment at the camp, the first controlled trial of drug treatment among shackled people with mental problems in West Africa.

The findings were mixed: Drug treatment, mostly for psychosis, blunted day-to-day symptoms of hallucinations and delusional thinking. But it did not reduce the length of time people were held in chains at the camp.

“We are not going to medicate our way out of these kinds of human rights abuses,” said Dr. Robert Rosenheck, a professor of psychiatry at Yale University Medical School, who designed the trial and was a co-author of the report.

Dr. Angela Ofori-Atta, an associate professor of psychiatry at the University of Ghana School of Medicine and Dentistry, led the study and arranged access to chained participants at the prayer camp. She said that the treatment produced some dramatic individual improvements — one man, shackled for 10 years, became strikingly lucid for the first time in memory — and that more careful, and longer, follow-up likely would have found that chaining was reduced, at least somewhat.

“The implications are clear: symptom control through the solitary use of medications is not a means to reduce chaining,” wrote Dr. Vikram Patel and Dr. Kamaldeep Bhui, professors of global health at Harvard, in an editorial accompanying the study. “This study reaffirms the need for a comprehensive and humane approach for the management of psychosis.”

People are chained at prayer camps throughout West Africa that are mostlyy Christian retreats. Some are tiny and hidden, while others are sprawling places, with open-air churches and cafeterias that teem with people on holy days.

The pastors who run the camps and their followers believe that prayer and fasting are the best treatment for mental problems. Camp staffers remove the chains when they decide a person is no longer mentally troubled but consistently lucid, calm, reasonable. That can take days, months or even years, depending on the person and the camp.

The leader of the Mt. Horeb camp, about an hour’s drive from Accra, the country’s capital, allowed Dr. Ofori-Atta and a team of psychiatric residents to recruit chained attendees for the study. The team obtained consent in the usual way, explaining the trial and its risks to the people and their families in the Twi language native to the region.

Obtaining informed consent is an imperfect process even when engaging patients in the United States who live independently, let alone chained, impoverished West Africans, said Dr. Rosenheck. People held in chains are deeply vulnerable, often poor and uninformed about Western medicine; many are apt to agree to almost anything if the staff and religiousleader approve.

“You explain everything in detail, and you ask people. Still, it is as ambiguous a process there as it is here,” Dr. Rosenheck said. Yale’s Global Health Leadership Initiative worked with Dr. Ofori-Atta to develop the study. Funding came from the University of Ghana and Ghana’s health ministry.

In the study, the researchers monitored the mental well-being of 110 chained people. The vast majority had a psychotic disorder, like schizophrenia. Half got a diagnosis, using Western labels like schizophrenia and depression, and predominantly drug treatment. The other half continued as before, with no changes to treatment.

After six weeks, those on drugs showed clear improvements on a standard rating scale that tracks feelings of hostility, emotional withdrawal and hallucinations. The camp residents doing the ratings did not know which people were on medication and which were not.

“The improvements were about the same as we see in trials done in Western countries,” Dr. Rosenheck said. Yet the number of days each person spent in chains was identical in both groups: about 12 days on average, after the initial phase of the trial.

The reasons that treatment didn’t reduce chaining are not obvious, said Dr. Ofori-Atta, but may include the length of the trial itself. The decision to remove chains was the camp’s to make, and typically staff want to see steady improvement over time.

Dr. Ofori-Atta said that another factor was the abuse of recreational drugs. Some people in chains were addicts likely to return to using drugs if freed, so staffers were slow to turn them loose.

In that sense, the study is yet another demonstration that people have little chance of becoming fully well until they are reintegrated into a community with the supports they need, regardless of diagnosis or treatments.